Pneumatic tool



Dec. 16, 1947. FRANCS I 2,432,877 A PN EUMAT I C TOOL Filed March 4, 1944 A 5 Sheets-sheet 2 7179.4. if f5 f r 5 I l 55 5:4. 55

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PNEUMATIC TOOL Filed March 4, 1944 5 Sheets-Sheet 3 L o 42's francis Patented Dec. 16, 1947 PNEUMATIC TOOL Louis Francis, Union City, N. J., assignor of one-half to Mary Leinster Francis, Union City, N. J.

Application March 4, 1944, Serial No. 525,075

' 4 Claims. 1

This invention relates to pneumatic tools,

An object of this invention is to provide a valveless pneumatic tool which can be designed for either light or heavy work and which is operated from a fairly low fluid pressure, the fluid -being preferably air.

Another object of this invention is to provide a tool of this kind wherein the prime mover consists in air acting against a flexible apertured diaphragm, the aperture of the diaphragm being alternately closed and opened by reciprocating movement of a spring-pressed plunger having a valve-like head. The degree of air pressure against the diaphragm acts as a regulating medium for regulating the length of the stroke of the plunger, and the head on the diaphragm being so constructed that the air pressure will force the head away from the diaphragm thereby permitting exhausting of the air.

A further object of this invention is to provide a pneumatic tool which can be made either out of light metal or almost entirely out of wood, the device being valveless will not require close tolerances, and in one form of the invention, the spring for the plunger acts as a guide for the plunger while simultaneously providing a tensionable means to move the plunger on the return or inoperative stroke thereof.

A further object of this invention is to provide a pneumatic tool of this type which by reason of its simple construction can be produced at very low cost, thereby providing `a tool which is practical for small jobs and can also be used for large or heavy jobs, the tool being of such construction that it can be operated by pressure generated by a person or by pressure from other pressure source.

With the foregoing objects and others which may hereinafter appear, the invention consists of the novel construction, combination and arrangement of parts as will be more specifically referred to, and illustrated in the accompanying drawings wherein are shown embodiments of the invention, but it is to be understood that changes, variations and modications may be resorted to which fall within the scope of the invention as claimed.

In the drawings:

Figure l is a detail side elevation of a pneumatic tool constructed according to an embodiment of this invention, y

Figure 2 is a detail front elevation partly broken away and in section of the tool,

Figure '.5 is a sectional'view taken on the line 3-.3 of Figure 2,

Figure 4 is a detail side elevation of a modiiied form of this invention,

Figure 5 is a sectional view partly in elevation taken on the line 5-5 of Figure 4,

Figure 6 is a vertical section partly in detail of another form of this invention,

Figure 7 is a sectional view taken on the line 1-1 of Figure 6, and

Figure 8 is a modified form of handle for use with the invention shown in Figures 1 and 2.

Referring to the drawings and first to Figures l, 2 and 3, the numeral I0 designates generally a frame or handle which includes a pair of forwardly convergent frame members II and I2 which may, if desired, be integral with each other and which terminate at their forward ends ina truncated V-shaped body I3.

The frame members II and I2 at their upper or rear ends are connected together by a connecting member I4 which may be integral with the upper or divergent ends of the frame members II and I2. The body I3 is formed centrally thereof with a bore I5 and aplunger, generally designated as I6, which is formed of an elongated rod I1 and a head I8 is slidable in the bore I5.

A block or annular body I9 is positioned adjacent the upper or divergent ends of the frame members II and I2 and is formed on the forward or lower side thereof with an air chamber 20. The block or body I9 is formed centrally thereof with an air intake opening 2I and an air pipe 22 communicates with the opening 2| and is adapted to be connected to a suitable source of air or gas pressure supply. A spring-pressed valve 23 is interposed in the pipe 22 and includes a button 24 which is spring-pressed to hold the valve 23 in normally closed or out off position. The body I9 is positioned between a pair of eutouts 24a and 25 which are formed in the inner sides or edges of the frame members Il and I2.

A cup-shaped resilient diaphragm 26 engages against the lower or outer end of the body I9 and is formed centrally thereof with an opening 21 so that air from the chamber 2B may be released from the chamber when the head I8 moves downwardly on its operating stroke. A anged cap 28 is threaded onto the block or body I9 and tightly holds the diaphragm 26 against the lower end of the block I9.

A spring 29 is disposed about the rod I1 bearing at one end against the lower side of the head I8. The spring 29 extends through the bore I5 and constitutes a guide for the rod I'I. The spring 29 is tensioned and tightly held within the bore l5 by means of a plate 30 which is secured to one side of the body I3 by fastening members 3|. The plate 30 on the inner face thereof is formed with a groove 32 Within which the convolutions of the spring I9 engage and the plate 30 may be loosened so as to adjust the endwise position of therspring 26, in order toprovide for the desiredtension on the spring 2,9.

The plunger rod at its lower or operating end has threaded thereon a cap or coupling member 33. The coupling member or cap 33 is formed with interior threads 34 and anvimpact tool or chisel 35 is threaded into the lower end of the cap 33. The tool 35 maybe wofany desired shape being shown as pointed at its operating end, but it will be understood that this tool may be flat or in the form of a chisel, -or-may be formed with a rivet forming or upsetting lower end.

A handle 36 is disposed at the upper end of the frame IU and thehandle 36 has secured thereto a pair of dowels por 4pins 31 which are slidable in openings 38 formed inthe upper ends of the frame members and l2. The pins or dowels 37 `have extending transversely therethrough limiting pins 319 Hwhich are slidable in elongated slots 40 "formed inthe arms or frame members and I2. The handle'36-is cushioned with respect to the frame |,0by means of a pair of springs 4| which engage about vthe pins or dowels 3'! and at `their lower or outer ends are seated in sockets 42 concentricto'the openings 38.

Referring now to Figures 4 and '5, there is disclosed a modiiied form of this pneumatic tool whichmay be made quite small for use with rela tively low air or gas pressure. Thetool disclosed in Figure '5 includes an elongated guide which is formed Witha central bore 44. A pair of oppositely extending arms -45 are Acarried by or formed integral with the upper'end ofthe guide 43 .and an annular member 46. is secured between the upper ends of thearms 45. The annulus 4'6 is formed with interior threads 41 and is provided at its lower end With an annular flange 48. A plug v49 is threaded into the annulus 46 from the upper end'thereof and is formedon the lower side thereof ,with an air chamber '58.

A disc-shaped and inwardly cupped diaphragm 5| is adapted 'to seat on 'the flange "8 and is tightly held on the flange 48'by the vplug 49. A

washer '52 is interposed Vbetween `the lower end` of the plug 49 and the yupper sid-e of the diaphragm 5|. A tube 5,3 is conneetedto'the plug 49 centrally vthereof and communicates with the chamber 50. A wing nut 4`514 is -Xed relative to the tube 53 so 4that the plug l49 may be readily adjusted orremoved with respect Yto V.the annulus v46. Ahose'55 engages the upper end of the tube 53 and;may be connected toany suitable source of air pressure. VIn practice ,the tool 'herein disclosed is sulciently small so that the air pressure generated in the lungs of a person may readily operate the device.

Aplunger generally designated as 56 is adapted to b e reciprocated bythe air pressure in the chamber ,'50 and also by means off a spring 5l. The plunger 5,6 includes an elongated plunger rod 58 which is slidable in the guide 43-and terminates at its lower end in a threaded portion 59 so that any desired tool maybe mounted on the lower end of therod 58. A cup-shapedhead 68 is secured to the upper end of 'the rod 58 and bears against the diaphragm f5.1, the latter having a central openingil whichjisnormally closed when .the head 158 is in Acontact with the lower or outer side of `the diaphragm 5|.

Referring now to Figures 6 and 7, there is disclosed a pneumatic tool which may be designed for fairly heavy duty. The tool shown in Figures 6 and 7 includes a housing 62 which is formed with a cylindrical flange 63 having exterior threads 64. The flange 63 forfms an air chamber 65 within the housing 62 and a exible diaphragm 66 engages against the lower end of the flange 63. The diaphragm 66 is tightly held against the lower end of the ange 63 by means of a flanged cap 61 which is threaded onto the flange .63. The-housing 62 also includes a reduced diameter nipple 68 having exterior threads 69-011 which acap 10 is threaded. A gasket 7| is interposed-between the cap I0 and the upper end of the nipple 68. The cap 68 has secured .centrally thereof 'upwardly extending elongated guide tube 'I2 within which an elongated plunger rod "I3 is slidably mounted.

The rod 'I3 has secured thereto at a point intermediate the lengththereof a cup-shaped head I4 which is adapted-to engage against the lower or outer side of the diaphragm 66, the latter having a central opening -"|5 through'which the rod 'i3 extends and which provides for release of air from the chamber 65. 'Ihe -rod 13 at its lower end is formed-witha tool or cutting head '|6 out it will be understood that if desired the lower end of the rod 13 may be threaded after the manner of the rod forvdetachably receiving a suitable tool. 'Ihe rod 'I3 is constantly urged upwardly to maintain the head 'I4 .against the diaphragm 66 by means of a spring TI. The spring 'il is disposed within the tube 'l2 and is connected at its lower Vend tothe upper end of the rod 1.3 andjs connected atits upperend to a transversely extending pin or bolt V'1,8 extending through the tube '12. A cap '19 is also threaded on the upper end ofthe tube I2 vso as to close this upper end.

The air chamber 65 is connected to a source of air pressure supply by means of Ya pipe.8 .which is connected to v-therhousinglZ and communicates at one end with the chamber 65. The other end of the pipe B0 isadapted tobezconnectedto a suitable sourceof Aair or gas pressure supply. A spring-closed valve '8| is interposed -in the pipe 38 and has an-Qperatinghandle orknob 82 positioned at a point convenient -forengagement by one hand or iinger of theV operator.

In order to provide `for-relievingithe hand of undue rvibrations .which .are caused when Vthe valve 8| is opened and :the plunger, which includes the rod"|3 and the head '|.'4,.is. rapidly vibrating, I have provided a handle .83 vwhich is slidable on the tube 12. The handle 83 is cush- I ioned with respectto the tube '|2 by-means of a lower spring-8`4 and anupper spring 85. The'two springs 84 and85 hold the handle'83 in a neutral position and will permit vibration of the tool when `the valve 8| -is opened without communicating such vibration to thehand of the operator.

Referring-now vto Figure-8, there is disclosed a modified form Vof cushioning means for the tool shown in Figures 1 and 2. In the present instance, the frame Ia has xedly securedito the upper end thereof a handle36a, A longitudinally bowed spring l86 engages vthe upper side of the handle 36a and is formed at the opposite yends thereof with elongatedslotsi'l. y.A screw or fastening member 88 extends through ,the slots v8'! and into the opposite end :portions of the'handle 36a so that the central orbowed portion of the spring 86 may be flexed inwardly thereby cushioning the vibrations ofthe frame Illa within the hand of the operator.

In the use and operation of this tool, the several forms operate in a similar manner. The tool or head 35 is engaged with the desired article and the handle 36 grasped in one hand with a thumb or linger pressed against the button 24. When the button 24 is pushed inwardly, the chamber 29 will be communicated with the source of air o-r gas pressure supply and pressure in chamber 20 will liex the diaphragm 26 outwardly. The air pressure will also be suflicient to move the head I8 out of contact with the lower or outer side of the diaphragm 26 so that the upper side of the head I8 which also constitutes a valve will be disengaged or unseated and the air from the chamber 20 will be exhausted through the diaphragm opening 21.

Spring 29 will return the plunger I6 to provide for engagement of the head I8 with the diaphragm 26 which will be flexed inwardly by the impact of the head I8 and the tension of the spring 29. The air pressure in the chamber 20 will immediately be built up sufficiently to again move the plunger I6 outwardly or downwardly on its operating stroke and in practice the plunger I6 will vibrate at a very rapid rate. The length of the stroke of the plunger I6 will depend in great part not only upon the tension of the spring 29 but also upon the degree of air pressure present in chamber 20.

This to-ol provides a valveless pneumatic tool which may be made either substantially entirely out of wood or light metal and in practice, the tool is designed as a fairly light tool but if a heavier tool is desired, it is only necessary to add weight to the frame Il] or to make the frame I9 out of heavier metal, such as steel or the like. The amount of air pressure necessary to vibrate the plunger I6 can be regulated in part by the flexibility of the diaphragm 26. In other words, where a fairly low air pressure is available, the diaphragm 26 may be made out of quite thin rubber or other flexible material.

Where heavy air pressure is available the diaphragm 26 may be made fairly thick. In the event the diaphragm 26 should beco-me worn or split, a new diaphragm can easily and quickly be inserted by unthreading the ange cap 28, the plunger I6 being pulled outwardly so as to disengage the head I8 from the diaphragm. The new diaphragm may be mounted in place of the worn diaphragm and the cap 28 replaced,

Where the plunger I6 is made out of wood, the exterior of the rod I'I may be coated with graphite or other suitable lubricant so that the rod II will freely slide within the spring 29. This tool has been designed for use in chipping rust, upsetting rivets of either small o-r large size, and may also find varied uses where a vibratory tool can be used. It will therefore be understood that I do not wish to be limited to the use of this tool as a tool yfor only chipping rust, driving nails, upsetting rivets or the like.

It will be understood that the term pneumatic too-l or tools as used herein contemplates any device or mechanical application of the disclosure made herein wherein the prime mover consists in air or other fluid pressure acting against a flexible apertured diaphragm as hereinbefore described.

What I claim is:

1. A pneumatic tool comprising a frame formed of a forward body, a pair of spaced arms extending rearwardly of said body, said body having a lengthwise bore, a plunger formed of a stem slidable in said bore and a head movable between the inner edges of said arms, a housing fixed between said arms rearwardly of said body, said housing being formed of a pressure chamber and a diaphragm having 'a central exhaust opening, means communicating said chamber with a source ci pressure supply, and spring means about said stem constantly urging said plunger rearwardly into contact with said diaphragm for normally closing said opening.

2. A pneumatic tool as set forth in claim 1 which includes means whereby said spring means may be tensioned.

3. A pneumatic tool comprising an annular housing, a flexible diaphragm having a central opening mounted in one end of said housing, a tubular guide extending from the opposite end of said housing, a reciprocable plunger including an elongated rod extending through said housing and having one portion thereof slidable in said tubular guide, a head fixed to said rod and normally engaging against said diaphragm for closing said opening, spring means in said guide connected to said rod for normally holding said head against said diaphragm, and means connecting said housing with a source of fluid pressure supply.

4. A pneumatic tool comprising a frame formed of a forward body, a pair of spaced arms extending rearwardly of said body, said body having a lengthwise bore, a plunger formed of a stem slidable in said bore and a head movable between the inner edges of said arms, a housing fixed between said arms rearwardly of said body, said housing being formed of a pressure chamber and a diaphragm having a central exhaust opening, means communicating Said chamber with a source of pressure supply, and spring means about said stem constantly urging said plunger rearwardly into contact with said diaphragm for normally closing said opening, said spring means being snugly disposed in said bore and constituting a bearing for said stem.

LOUIS FRANCIS.

REFERENCES CITED rThe following references are of record in the file of this patent:

UNITED STATES PATENTS 

